Accurate high-speed displacement measurement method for slender structures based on the sampling moiré method.

Area of Science:

• Mechanical Engineering
• Optical Metrology
• Materials Science

Background:

• Measuring width-direction displacement in elongated structures is challenging.
• Existing methods may lack accuracy, speed, or full-field coverage.
• Elongated structures like blades require precise displacement monitoring during operation.

Purpose of the Study:

• To propose a novel, indirect displacement measurement method for width-direction displacement.
• To address the limitations of current measurement techniques for elongated structures.
• To provide a high-accuracy, high-speed, and full-field measurement solution.

Main Methods:

• Fabrication of an oblique 45° grating.
• High-speed camera imaging of the grating.
• Length-direction phase analysis using the sampling moiré method.
• Calculation of width-direction displacement from phase differences.

Main Results:

• The method demonstrates high displacement measurement accuracy and stability.
• Successfully captured displacement-time curves for simulated vibrating elongated structures.
• Obtained frequency spectra of vibrating components via Fourier transform.
• Verified effective reflection of displacement changes in vibrating blades.

Conclusions:

• The proposed method offers a novel approach for indirect width-direction displacement measurement.
• It provides high accuracy, speed, ease of operation, and full-field coverage.
• This technique holds significant scientific and engineering value for elongated structures.